If your amplifier has a 3.5mm jack, then get an audio cable with 3.5mm audio plug on both end (they are cheap and available on local computer store, ebay, electronic store, etc) and connect where you plug your headphone on your laptop to the jack of the amplifier with the cable.
If the amplifier has a 2.5mm or 6.5mm jack, then use a size adapter as well.
yeah, amplifier amplifies anything including static and imperfection on the audio source. Do you have a microphone on your computer and did you disable it/unplug it? Just one thing that will reduce background noise.
no, mic was di'd to amp, i just took feed from headphone socket on laptop and used adaptor to input to std jack on amp. I could just try better cables I suppose but just wondered if there was a better way of doing it like via hdmi or usb ports etc?
+1^. Set the level at 50% as a start. Also, while in the audio CP, try to Mute any inputs that aren't used. If quality is important, you can step up to a USB audio device, which may give you line level output (not amplified Headphone output).
its a laney theatre 120x4 amp ie 4 channels (thats all I can tell you... sorry), the other channels used for di mic (sm58) and di yamaha apx 6 guitar with peavey speakers. always worked fine with my playback unit (until it blew up live) so used the laptop to get me through the gig however this buzzing noise wasnt good! as was mentioned earlier, the cables I was using werent particularly good as it was last minute fix but now want to go on using the laptop and not sure of the best way to do it. Hope this helps and thanks for your reply
Use the shortest cable that you can use and buy a decent quality one. You don't need to buy the most expensive Monster Cable you can find but make sure it's a nicely insulated one as Pyree said. If you go to a music instrument or Pro Audio shop there should be a good selection to choose from.
Make sure your computer is plugged into the same power strip at the amp so they will have a common ground. there are also some external USB sound cards you can purchase for better than CD quality output.
Without getting to complicated, you should look for a good driver or software to be bundled. Crappy drivers will make things frustrating. Look at some from Presonus and Maudio. Both should have some lower and high end models. Compare the specs and then use that as a reference to compare by. I would stay away from the no name brands.
I user a Maudio card in my desktop but I would think the USB or Firewire interfaces.